In this work,we report the preparation of a series of electroluminescent(EL)devices based on a high-performance polymer,poly(p-phenylene benzobisoxazole)(PBO),and their optoelectronic properties,which have been rarely explored.The device structure is optimised using a complex cathode structure of tris-(8-hydoxyquinoline)aluminium(Alq3)/LiF/Al.By tuning the thickness of the Alq3layer,we improve the device efficiency dramatically in an optimized condition.Further analysis reveals that the Alq3layer in the complex cathode structure acts as a hole blocker in addition to its electron-injection role.A green light emission with a maximum brightness of 8.7×103cd/m2and a moderate current efficiency of 4.8 cd/A is obtained.These values are the highest ever reported for PBO devices.The high operational stability demonstrated by the present device makes it a promising tool for display and lighting applications.A new material is added to the selection of polymers used in this field up to now.
Bulk heterojunction organic solar cells(OSCs) based on the blend of poly(2-methoxy-5(2'-ethyl-hexyloxy)-1,4-phenylenevinylene(MEH-PPV) and [6,6]-phenyl C61 butyric acid methyl ester(PCBM) with different weight ratios(from 1:3 to 1:5) have been fabricated and the effect of annealing treatment on the performance of OSCs has also been studied.Experimental results point to the best optimized doping concentration 1:4 for MEH-PPV:PCBM.Furthermore,it is found that the devices with annealing treatment at 150℃ with 8 min show better performance compared with the devices without treatment.The series resistance(Rs) is decreased,while the shunt resistance(Rsh) increased by nearly 1.5 times.The short-circuit current density(Jsc) and fill factor(FF) are improved by annealing treatment.As a result,the power conversion efficiency(PCE) of the devices increases from 0.49 % to 1.21 % with the ratio of 1:3 and from 1.09% to 1.42% with the ratio of 1:4.
SONG JingLuXU ZhengZHANG FuJunZHAO SuLingHU TaoLI JunMingLIU XiaoDongYUE XinWANG YongSheng
In this paper,a new upconversion luminescent material co-doped with Erbium and Ytterbium is reported. The upconversion luminescence transition routes and related properties are studied. The results show that the absorption and emission intensities under excitation of 980 nm laser increase with the increase of the Yb3+ concentration. The red emission is stronger than the green emission. The energy transfer process plays an important role in the upconversion mechanism.
ZHAO SuLing1,XU Zheng1,WANG LiHui2 & S. Wageh3 1 Institute of Optoelectronic Technology,Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University),Ministry of Education,Beijing 100044,China
